The invention relates to clarifiers, and more specifically, to clarifiers having flocculating energy dissipating well arrangements.
Clarifiers typically include a tank, a center influent pier, an outer well, and a sludge removal mechanism. The tank includes a bottom and a wall that extends upwardly from the perimeter of the bottom such that the tank is capable of containing a liquid. The influent pier projects from the bottom of the tank along an axis and includes ports that initially direct a solution containing suspended solids outwardly. The clarifier includes a cage that is rotatably supported at the top of the influent pier with a bearing. The cage is a vertical box type truss structure that surrounds the influent pier and supports the sludge removal system and the outer well. The solution flows from the influent pier to the wall of the outer well which dissipates the energy of the influent flow and which promotes flocculation of the solution. During flocculation the solids suspended in the solution collide and form flocculants that settle out from the solution onto the tank floor to clarify the solution. The clarified liquid is removed from the tank through outlet ports located along the tank wall near the surface of the solution, and the sludge removal mechanism retrieves the sludge that settles from the solution onto the bottom of the tank.
Some clarifiers include a flocculating energy dissipating well arrangement (xe2x80x9cFEDWAxe2x80x9d) that is positioned between the center influent pier and the outer well to further dissipate the flow energy of the solution and generate increased flocculation of the solution. The FEDWA is also supported by the cage, and the cage includes a plate that defines a planar horizontal surface that is positioned just below the inlet ports of the influent pier. The FEDWA includes outer baffles that are positioned outside of the cage. The outer baffles each include a vertical portion and a horizontal portion that is coplanar with the cage plate.
By way of this arrangement, the FEDWA dissipates the flow energy of the solution discharged from ports of the influent pier by separating the flow into a bi-directional flow having a first flow portion and a second flow portion. The first flow portion is directed in a first direction that is generally tangential with respect to the axis of the influent pier and the second flow portion is directed in a second direction that is opposite to the first direction of the first flow portion. The flow exits the FEDWA and flows around the outer well which further dissipates the flow energy and prevents the flow from moving directly from the FEDWA to the wall of the tank.
The flocculating energy dissipating well arrangement (FEDWA) of the present invention provides tri-directional flow by positioning horizontal portions of outer most baffles below the vertical level of the cage plate. The tri-directional flow results in superior diffusion and dissipation of flow energy of the influent flow by directing flow back toward the influent pier causing the solution that is discharged from the ports of the influent pier to flow back and impinge onto itself creating another area of confluence. In addition, the tri-directional flow prevents flocculants from depositing onto the horizontal portions of the baffles. The additional area of confluence below and outside the FEDWA promotes passive flocculation of the suspended solids promoting increased settling rates.
The FEDWA of the present invention also allows the clarifier to be operated without an outer well by alone providing sufficient flow energy dissipation and flocculation of the solution. Specifically, the FEDWA of the present invention provides tri-directional flow that results in increased directional changes in the flow of the solution which increases flocculation and energy dissipation allowing the outer well to be removed from the clarifier. Removal of the outer well decreases the weight being supported by the bearing of the cage and thereby increases the service life of the bearing to provide a cost savings.
The present invention is directed to a clarifier that is used to separate suspended solids from a solution. The clarifier includes a tank, an influent pier, and a FEDWA. The tank includes a bottom and a wall that extends upwardly from the bottom. The influent pier projects upwardly from the bottom of the tank along an axis. The influent pier includes ports that direct flow of the solution outwardly from the influent pier. The FEDWA separates the flow of the solution that is discharged by the ports and that flows into the tank. The separated flow of the solution includes first, second, and third flow portions. The first flow portion is directed in a first direction that is generally tangential with respect to the axis of the influent pier. The second flow portion is directed in a second direction that is opposite to the first direction of the first flow portion. The third flow portion is directed in a third direction toward the axis.
The present invention is also directed to a FEDWA that is used with a clarifier. The FEDWA includes a cage and outer baffles. The cage includes a plate, and the outer baffles are mounted to the cage and positioned outside of the cage. The outer baffles include vertical portions and horizontal portions that extend from the vertical portions. The horizontal portions are positioned below the plate of the cage.
In addition, the present invention is directed to a clarifier that includes a tank, an influent pier, and a FEDWA. The tank includes a bottom and a wall extending upwardly from the bottom. The influent pier projects upwardly from the bottom of the tank along an axis and includes ports that direct flow of the solution outwardly from the influent pier. The FEDWA separates the flow of the solution discharged by the ports and flowing into the tank. The clarifier does not include any well between the FEDWA and the wall of the tank.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.